Dolania

Distinguished from other mayflies by vestigial, twisted legs in adults; exceptionally short adult lifespan (under 30 minutes); large eggs (~1 mm diameter, among largest in mayflies); and sand-burrowing nymphal habit. Male genitalia distinctive: penis twice length of forceps. Nymphs lack tusked mandibles and possess unique gill arrangement with protective spiny leg modifications.

Streams and rivers of coastal plains; nymphs burrow into sandy riverbeds in areas with rapidly moving, fairly clean sand.

Southeastern United States coastal plains; recorded from Florida to South Carolina, northward in coastal plain streams.

Adults emerge before dawn in early summer; emergence synchronized with males appearing ~1.5 hours before sunrise. In Florida: late April to early May; South Carolina: first half of June.

Nymphs are predatory, feeding on larvae of chironomids (midges) and ceratopogonids (biting midges).

Two-year life cycle: eggs deposited in early June, hatch following spring; nymphal development requires 12–14 months; synchronous adult metamorphosis with >95% emerging during first week of emergence period. First-instar larvae are exceptionally large (2.5–5 times length of other mayfly first instars) due to large egg size.

Nymphs are sand-burrowers, using forelegs and head to excavate sediment. Adult emergence is highly synchronized and crepuscular. Males patrol 15–20 m river stretches seeking females; continue until drowning from exhaustion. Females mate immediately upon emergence, oviposit, and die within ~5 minutes. Males molt to imago within ~5 minutes of emergence; females remain in subimago form.

Predatory nymphs function as infaunal predators in sandy stream substrates, consuming dipteran larvae. Brief adult emergence represents a concentrated nutrient pulse to aquatic and riparian food webs.

Generally uncommon and of limited direct human importance; may serve as indicator of clean, sandy stream habitats.

• BehningiaSame family (Behningiidae); shares large egg size, abbreviated adult lifespan, and predatory sand-burrowing nymphal habit. Dolania distinguished by monotypic status, specific wing and genital morphology, and even more extreme adult lifespan reduction.
• Other EphemeropteraMost mayflies have longer adult lifespans (hours to days), smaller eggs, herbivorous or detritivorous nymphs, and well-developed adult legs. Dolania's vestigial legs, predatory nymphs, and 30-minute adult life are unique among mayflies.

• sand-burrowing
• predatory nymph
• shortest adult lifespan
• synchronous emergence
• large eggs
• vestigial legs
• coastal plain
• southeastern US

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Life History, Developmental Processes, and Energetics of the Burrowing Mayfly Dolania Americana
• The reproductive life history of the predacious, sand-burrowing mayfly Dolania americana (Ephemeroptera: Behningiidae) and comparisons with other mayflies